This discussion is closed.
Mr. Brightside
Badges: 0
#1
Report Thread starter 15 years ago
#1
basically diff indices
6
----
5x^3 + 4x^3
now the 4x^3 bit is simply 12x squared but the six over 5x^3 is confusing me a bit, would it be just 6/5 times x^3 and then differentiate it. that seems too easy. any suggestions?
0
El Stevo
Badges: 1
Rep:
?
#2
Report 15 years ago
#2
rewrite it as (6/5)(x^-3) + 4(x^3)
0
Mr. Brightside
Badges: 0
#3
Report Thread starter 15 years ago
#3
(Original post by El Stevo)
rewrite it as (6/5)(x^-3) + 4(x^3)
what i said then ok cool
0
username9816
Badges: 12
Rep:
?
#4
Report 15 years ago
#4
(Original post by Mr. Brightside)
basically diff indices
6
----
5x^3 + 4x^3
now the 4x^3 bit is simply 12x squared but the six over 5x^3 is confusing me a bit, would it be just 6/5 times x^3 and then differentiate it. that seems too easy. any suggestions?
d/dx {6/(5x^3) + 4x^3} = d/dx {(6/5)(x^-3) + 4x^3} = (6/5)(-3)(x^-4) + (4)(3)(x^2) = 12x^2 - 18/(5x^4) = (60x^6 - 18)/(5x^4)

Nima
0
El Stevo
Badges: 1
Rep:
?
#5
Report 15 years ago
#5
(Original post by Mr. Brightside)
what i said then ok cool
no... you said (6/5)*(x^3)... what i said has a very important difference... (6/5)*(x^-3)
0
idiopathic
Badges: 15
Rep:
?
#6
Report 15 years ago
#6
(Original post by El Stevo)
no... you said (6/5)*(x^3)... what i said has a very important difference... (6/5)*(x^-3)
his

6
----
5x^3


is 6/(5x^3) ?
0
El Stevo
Badges: 1
Rep:
?
#7
Report 15 years ago
#7
yes... but his
(Original post by Mr. Brightside)
would it be just 6/5 times x^3 and then differentiate it
is wrong...
0
idiopathic
Badges: 15
Rep:
?
#8
Report 15 years ago
#8
oh yeh ok then.
0
X
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

How will you be receiving your results?

Going into school to pick them up (180)
33.33%
Receiving them online / by email (270)
50%
I still don't know (90)
16.67%

Watched Threads

View All